iOS 4.1 Redsnow 0.9.6B2

I just got the new version of redsn0w to jailbreak my iphone 3gs new BOOTROM.

I used pwnage tool from VMWare to get my firmware, now when I put the pwned firmware on redsnow, it doesn't recognize it. Do I need to put the official firmware in Redsn0w? I just need to put it in DFU mode, that's all.